Organotrialkoxysilane-mediated synthesis of functional noble metal nanoparticles and their bimetallic for electrochemica
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MRS Advances © 2020 Materials Research Society DOI: 10.1557/adv.2020.305
Organotrialkoxysilane-mediated synthesis of functional noble metal nanoparticles and their bimetallic for electrochemical recognition of L-tryptophan P.C. Pandey1, Shubhangi Shukla1, Govind Pandey2, and Roger J. Narayan3 1
Department of Chemistry, Indian Institute of Technology (BHU), Varanasi, India. [email protected]
2
Department of Pediatrics, King George Medical University, Lucknow, India, [email protected]
3
Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, NC, USA; [email protected]
Effective and pH-sensitive electrochemical monitoring of L-tryptophan using noble metal nanocatalysts was evaluated in this study. This work examined the electrocatalytic influence of nanoparticles on the oxidation of amino acids with the variation of pH in working media. Bimetallic nanohybrids of palladium, silver, and gold (e.g., Pd/Ag and Pd/Au nanoparticles) were processed using organofunctionalized alkoxysilanes (3aminopropyltrimethoxysilane (3-APTMS) and 2-(3,4-epoxycyclohexyl) ethyltrimethoxysilane (EETMOS)) via a sequential reduction pathway. Transmission electron microscopy (TEM) demonstrated the role of the alkoxysilanes in determining the size of the nanoparticles and the distribution of metals in the core-shell configuration. The cluster-like morphology of PdNPs was remodeled to form bimetallic nanomaterials (PdAuNPs and Pd-AgNPs) with a core-shell structure. Enhancement in the electrooxidation behavior was shown to depend on the nanomaterial and the pH of the medium. The PdAgNPs modified electrode exhibited high sensitivity and selectivity, with characteristic amplification in cathodic peak current at lower oxidation potentials (0.659 V, 0.782 V, and 0.890 V at pH values 4, 7, and 9, respectively) due to its greater stability. Differential pulse voltammetric (DPV) scans were recorded over a wide range of concentrations from 0.1 M to 1000M; the Pd-AgNPs modified electrode showed the lowest limit of detection of 0.1M at pH 4, 0.5 M at pH 7, and 0.5 M at pH 9. 1
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INTRODUCTION: Electrochemical and chromatographic biosensing of amino acids has remained an active area of research for several decades [1]. Various methods, including the twodimensional paper chromatographic approach, fluorescent approach, and optical approach for amino acid detection have been reported earlier [2]. Chromatographic and optical sensors are meant for bulk detection and often complex to handle; since amino acids are required in trace amounts for many processes, detection of amino acids at the molecular level is essential. Electroanalytical detection has been previously carried out on bare graphite paste (GP) using various modifiers, including methacry
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